1. Field of the Invention
The present invention relates in general to integrated circuits and in particular to a system on a chip.
2. Description of the Related Art
Sophisticated design and fabrication techniques are rapidly making practical systems-on-a-chip a reality. In turn, a broad range of personal and commercial hand-held appliances can be constructed which embody a high degree of functionality. These appliances include personal digital assistants, personal digital music players, compact computers, point of sale devices, and Internet access devices, to name only a few of the possibilities.
A number of factors must be addressed when designing a system-on-a-chip. Among other things, the device must be capable of interfacing with a broad range of input/output devices which may be required to support various potential user-defined applications. Moreover, the device must be power efficient while operating at high clock speeds. Additionally, this device should have a large address space to flexibly support a range of possible memory configurations and sizes.
According to the principles of the present intention, a system is disclosed which is fabricated on a single integrated circuit chip and includes a microprocessor operating from a high speed bus, a peripheral bus operating in conjunction with the high speed bus through a bus bridge, and sets of processing resources operating from high speed and peripheral buses. A first of the sets of the processing resources, operating from the high speed bus, includes a memory interface for interfacing the system with an external memory, a direct memory access engine for controlling the exchange of information between selected ones of the resources and the external memory through the memory interface, and a boot memory for storing boot code for initiating operation of system. A second set of resources, operating from the peripheral bus, includes an interrupt controller for issuing interrupt requests to the microprocessor in response to interrupt signals from selected ones of the system resources, a set of programmable timers for generating timed interrupt signals, and a phase-locked loop for generating timing signals for timing selected operations of system.
The inventive concepts allow for the construction of practical systems on a chip and similar high functionality integrated circuits. Advantageously, such devices can be used in a broad range of low power, compact personal and commercial appliances. Among other things, devices constructed in accordance with the present teachings can be used in personal digital assistants, personal digital music players, compact computers, point-of-sale devices, and internet access devices, to name only a few of the numerous possibilities.